Fuel cells, which are sometimes referred to as electrochemical conversion cells, produce electrical energy by processing reactants, for example, through the oxidation and reduction of hydrogen and oxygen. Hydrogen can be a very attractive fuel because it is clean and it can be used to produce electricity efficiently in a fuel cell. The automotive industry has expended significant resources in the development of hydrogen fuel cells as a source of power for vehicles. Vehicles powered by hydrogen fuel cells could be more efficient and generate fewer emissions than today's vehicles employing internal combustion engines.
In some fuel cell systems, hydrogen or a hydrogen-rich gas is supplied as a reactant through a flowpath to the anode side of a fuel cell, while oxygen (such as in the form of atmospheric oxygen) is supplied as a reactant through a separate flowpath to the cathode side of the fuel cell. The anode and cathode facilitate the electrochemical conversion of the reactants into electrons and positively charged ions (for the hydrogen) and negatively charged ions (for the oxygen). An electrolyte layer separates the anode from the cathode to allow the selective passage of ions to pass from the anode to the cathode while simultaneously prohibiting the passage of the generated electrons, which instead are forced to flow through an external electrically-conductive circuit (such as, a load) to perform useful work before recombining with the charged ions at the cathode. The combination of the positively and negatively charged ions at the cathode results in the production of non-polluting water as a byproduct of the reaction.
A conventional proton exchange membrane (“PEM”) fuel cell may comprise a solid polymer electrolyte membrane (or a proton exchange membrane) with electrode layers on both sides of the polymer membrane forming a membrane electrode assembly (“MEA”). The membrane electrode assembly may be positioned between a pair of gas diffusion media layers, each of which have a microporous layer formed on diffusion media, and a cathode plate and an anode plate are placed outside of the gas diffusion media layers. The components are compressed to form a fuel cell.
Fuel cells, however, suffer from drawbacks that can decrease the life of a fuel cell. For example, the electrode layers coated on both sides of the solid polymer electrolyte membrane may have a reduced bond at the interface resulting in a less durable fuel cell. In addition, the life of the membrane, and therefore, the fuel cell, may be shortened because of one of a MEA over-compression and a MEA under-compression occurring at the subgasket. The manufacturing processes used to form the MEA may cause over-compression where the membrane swells and creates a compressive load variance across the MEA. This can result in permanent deformation of various components making up the MEA. Under-compression also may occur due to manufacturing processes and can result in buckling of the membrane. The buckling of the membrane may cause one of the anode electrode and the cathode electrode formed thereon to crack.
Therefore, alternative fuel cells, reinforced catalyst composite structures, membrane electrode assemblies, and methods of fabrication are disclosed herein